Though first-round vaccinations continue to offer strong protections against hospitalization, Colorado's long-term care facilities must complete booster clinics in the next 10 days amid concerns of waning vaccine efficacy.
There have been increasing numbers of breakthrough infections — meaning cases among vaccinated individuals — in Colorado, health officials have said, as research emerges indicating the vaccine's protection against contracting COVID-19 wanes after several months. That's particularly worrisome for at-risk populations like the elderly and people with compromised immune systems, and it's why state leaders are currently pressing long-term care facilities to distribute booster doses to their residents.
Breakthrough infections are in part caused by waning immunity, said Rachel Herlihy, Colorado's state epidemiologist. Also exacerbating those infections is the spread of the delta variant, which is more transmissible than previous strains of the virus. Behavioral changes — fewer masks, less social distancing, more mobility — are also playing their part, she said.
A seminal study, published earlier this month in medical journal The Lancet, found that Pfizer and Moderna efficacy against infection dropped from 88% after the first month to 47% within five months. But the vaccine's efficacy against hospitalization remained high, researchers found: Even with the more transmissible delta variant, the doses offered 93% protection against hospitalization. As of Thursday afternoon, 78% of the 982 Coloradans currently hospitalized with COVID-19 are unvaccinated.
"We know that we're seeing waning immunity, but it does look like the impact of waning immunity is mostly around the risk of infection," Herlihy said. She and other state officials stressed that first- and second-dose vaccinations are more critical in protecting against the virus than boosters.
Federal regulators have yet to give full approval for booster doses. But they've given the green light for some: On Thursday, a federal vaccine advisory panel voted unanimously to allow Moderna booster shots to at-risk groups, including the elderly and those with compromised immune systems; Pfizer had previously received the same approval, and early data indicates a booster for the Johnson & Johnson vaccine significantly bolsters its efficacy.
Thomas Jaenisch, an epidemiologist and clinical researcher at CU-Anschutz, said he wasn't surprised the COVID-19 vaccines need a booster; he pointed to other inoculations, like those against various types of hepatitis, and said follow-up jabs are typical.
But it's still unclear, he said, if the additional doses will confer long-term immunity or if annual or semi-regular boosters will be needed going forward.
"From here on, it’s uncharted territory," he said.
Among the limited populations that are currently approved to receive boosters, Colorado has prioritized long-term care residents in particular. The state is requiring those facilities to complete all booster clinics by Oct. 25. Speaking at a press conference earlier this week, Gov. Jared Polis said that 18.3% of Colorado's 65-and-older population has already received a third dose and that 80% of clinics in long-term care settings have completed or scheduled their clinics.
Vaccination rates among those residents have long been high. They were among the first to be eligible to receive doses at the beginning of 2021, when the supply of vaccines was far more limited than it is now. Polis presented data indicating that 93.5% of residents have been fully vaccinated.
There's been less uptake among the staff serving those residents. Though it's improved from the spring, when it was in the 60% range, the workers' rate still stands 10 points below their charges.
Data published weekly by the state Department of Public Health and Environment provides an insight into various vaccine dynamics at play within those facilities. As of Oct. 13, there were 1,127 cases in Colorado's nursing homes and assisted-living facilities. But almost exactly half of those cases were among staff, a marked shift from mid-November 2020. At that point, when the pandemic had peaked to unprecedented levels, there were 1,655 resident cases — and just 116 infections among staff. The number of outbreaks now is similar to the number in November, as well: There are 138 outbreaks now, compared to 112 nearly a year ago.
According to data released Nov. 18, 183 residents had died in the outbreaks active at that point. That translated to about nine resident cases per death. Now, the ratio is roughly 17 cases per death.
Doug Farmer, whose Colorado Health Care Association represents nursing homes, said long-term care facilities are generally in a good place right now. The booster rollout, though on a fast timetable, has been relatively smooth.
"The number of outbreaks looks uh-oh," he said, "but the number of people — it's scarcely more than the number of outbreaks."
Herlihy said the state knows there's particular potential for breakthrough cases in long-term care facilities. Not only are those residents among the most vulnerable, but because they were also among the first to receive doses, their immunity from the vaccine may have waned more.
"You could say that it is quite possible that individuals who were vaccinated first are those who are increased risk," she said.
In El Paso County, where COVID-19 transmission is in a high plateau with 2,259 cases reported the past week, 23 long-term care facilities have had outbreaks, infecting 257 residents and staff members. Eighteen residents have died in those outbreaks, the data show.
The county public health department said the more contagious delta variant, high community transmission and waning immunity could be contributing to the outbreaks.
“It’s important to note that COVID-19 vaccines are not 100% effective; in times of higher incidence levels in the community, as we are seeing now, the risk for breakthrough infections increases,” spokeswoman Michelle Beyrle said in an email.
The Palisades at Broadmoor Park, an independent living, assisted living and memory care facility, experienced one of the outbreaks this fall with 12 cases, including 10 among residents; the facility has reported one death, state data shows.
The facility kept in constant contact with residents and families about COVID cases, isolated those who were positive and maintained effective infection control practices, said Constance Sablan, a spokeswoman for MBK Senior Living, the company that owns the facility.
“These steps work. Recent testing confirmed 100% negative COVID test results in our community. We’ll complete one more round of testing in which we expect to then be clear of COVID again,” she said.
The facility is planning to hold booster shot clinics on Oct. 25 and 26, and she expects they will be well-attended.
Sablan said it was difficult to know whether waning immunity played a role in the recent outbreak, but the facility would be encouraging the booster shots.
The Gazette contacted the eight El Paso County facilities that have seen COVID-19 deaths this fall. The Palisades was the only one to immediately respond.
The largest El Paso County outbreak was at MorningStar at Bear Creek, which has seen 36 cases, including 22 among residents and five deaths, state data shows.
Across El Paso County, 18,000 booster doses have been administered among the older adults and the immunocompromised, Beyrle said. The county has also vaccinated 70% of eligible residents with at least one dose of the vaccine. About 64% of eligible county adults are fully vaccinated.